U.S. patent number 3,927,823 [Application Number 05/394,443] was granted by the patent office on 1975-12-23 for blank of a foldable material such as cardboard and a tray erected therefrom.
This patent grant is currently assigned to Sprinter Pack AB. Invention is credited to Karl Rune Persson.
United States Patent |
3,927,823 |
Persson |
December 23, 1975 |
Blank of a foldable material such as cardboard and a tray erected
therefrom
Abstract
A blank of foldable material such as cardboard, aluminium foil
or the like, which is divided by folding lines into areas for
erecting a tray with a bottom, two opposite side walls with end
flaps and two opposite end walls with folded down edge flaps which
are adapted to lie over the folded in end flaps for the purpose of
locking these. The folding line between the bottom and each of the
end walls extends along an arc so that when folding up the end wall
this wall and the folded down edge flap will be kept in a bent
position, which locks the folded down edge flap.
Inventors: |
Persson; Karl Rune (Halmstad,
SW) |
Assignee: |
Sprinter Pack AB (Halmstad,
SW)
|
Family
ID: |
20294655 |
Appl.
No.: |
05/394,443 |
Filed: |
September 5, 1973 |
Foreign Application Priority Data
|
|
|
|
|
Sep 13, 1972 [SW] |
|
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11806/72 |
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Current U.S.
Class: |
229/171; 229/174;
229/186; 229/903; 229/905; 229/930 |
Current CPC
Class: |
B65D
5/2023 (20130101); B65D 5/2038 (20130101); B65D
5/248 (20130101); Y10S 229/93 (20130101); Y10S
229/905 (20130101); Y10S 229/903 (20130101) |
Current International
Class: |
B65D
5/24 (20060101); B65D 5/20 (20060101); B65D
005/36 () |
Field of
Search: |
;229/30,31R,31FS,41B |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Christian; Leonard D.
Attorney, Agent or Firm: Ostrolenk, Faber, Gerb &
Soffen
Claims
What is claimed is:
1. A blank of foldable material for forming a folding tray
comprising:
a bottom; opposite sidewalls articulated along a fold line at one
side thereof to said bottom; an edge flange articulated along a
fold line to another side of each sidewall and adapted to be folded
to lie against an exterior surface of the associated sidewall;
opposite endwalls articulated at one end thereof to said bottom
along an arcuate-shaped folding line; an edge flap articulated to
another end of each endwall along a substantially straight folding
line; locking means extended from and articulated along a fold line
at opposite ends of each sidewall; each sidewall and each endwall
being adapted to be erected in a common direction relative to the
bottom for assembly of the tray; each edge flap being folded over
to lie against an adjacent endwall, each locking means being folded
to lie between an adjacent endwall and the associated folded-over
edge flap, whereby the curved shape of the erected edge flaps and
endwalls retain the enclosed locking means therebetween to maintain
the respective endwalls and sidewalls in the erected condition.
2. A blank for forming a folded tray as set forth in claim 1,
wherein each arcuate-shaped folding line causes each endwall to
assume a concave contour along its exterior surface when
erected.
3. A blank for forming a folded tray as set forth in claim 1,
wherein each arcuate-shaped folding line causes each endwall to
assume a convex contour along its exterior surface when
erected.
4. A blank for forming a folding tray as set forth in claim 1,
wherein said locking means comprises locking flaps extended from
and articulated along a fold line at opposite ends of each sidewall
edge flange and adapted to be folded to lie between each endwall
and the associated folded-over edge flap to lock the sidewalls when
the folding tray is in the assembled condition.
5. A blank for forming a folding tray as set forth in claim 4,
wherein said locking means further comprises articulated corner
gusset means for integrally and foldably connecting each sidewall
to each endwall at the corners therebetween, said corner gusset
means being adapted to lie flush against an associated endwall and
beneath an associated edge flap when the folding tray is in the
erected condition.
6. A blank for forming a folding tray as set forth in claim 1,
wherein said locking means comprises end flaps extended from and
articulated along a fold line at opposite ends of each sidewall and
spaced from said endwalls; said end flaps adapted to be folded to
lie between each endwall and the associated folded-over edge flap
to lock the sidewalls in the assembled condition.
7. A folding tray formed from a blank of foldable material
comprising: a bottom; opposite sidewalls articulated along a
folding line at one side thereof to said bottom; an edge flange
articulated along a folding line to another side of each sidewall;
locking flaps extending from and articulated to opposite ends of
each edge flange along a fold line; opposite endwalls articulated
at one end thereof to said bottom along an arcuate-shaped folding
line; and edge flap articulated to another end of each endwall
along a substantially straight folding line; said edge flanges
being adapted to be folded over to lie against an exterior surface
of the associated sidewall with said locking flaps being adapted to
be folded in towards one surface of the adjacent endwall, each edge
flap being folded over to assume a curved shape and to lie against
the associated endwall with the adjacent locking flaps being
positioned therebetween, whereby the respective curved edge flaps
and locking portions lock the respective endwalls and sidewalls in
an assembled condition.
Description
The present invention relates to a blank of a foldable material
such as cardboard, which is divided by means of folding lines into
areas for raising a tray with a bottom, two opposite side walls
with end flaps and two opposite end walls with edge flaps folded
down and overlapping the end flaps folded in for locking these.
Hitherto the end flaps and edge flaps have normally been locked by
the action of an additional agent such as an adhesive or by
arranging slots in the end walls.
The object of the invention is to provide a blank which can be
erected to a tray with the end flaps and edge flaps locked without
the assistance of an adhesive or other additional means and without
the need to arrange slots in any of the tray sections.
This is achieved according to the invention by means of a blank
which is characterized according to the invention by the fact that
the folding line between the bottom and each of the end walls
extends along an arc so that when folding the adjacent end wall,
this wall and the associated edge flap folded down will be held in
a bent position, thus locking the folded edge flap and hence the
end flaps. The invention is therefore based essentially on the fact
that folding down the edge flap against a plane end wall by folding
along an essentially straight folding line will not effect a
locking action as long as the end wall and the edge flap are plane,
whilst bending of the end wall and the edge flap when the edge flap
is folded down will prevent the edge flap from dropping out away
from the end wall.
The blank may be provided with known surface coats to resist
liquid, the coat consisting of heat sealable plastic, which may
also be of a known type, to withstand temperatures of over
200.degree.C, as is the case when the tray is to be used, for
example, for ready cooked food or other food intended for heating,
such as baking powder mixtures which after adding liquid can be
heated and baked into cakes or bread. The tray according to the
invention may also be used to advantage for ice-cream and other
deep-frozen foods. It is also possible to use the materials
according to the invention, which include cardboard, thin aluminium
foil or similar materials, for domestic purposes where one can very
easily erect the tray oneself and store food in the tray so that
the tray can be placed directly into the oven for heating. After
use the tray can be thrown away, thereby avoiding washing up
conventional heating vessels.
An important advantage of the tray according to the invention,
particularly with regard to deep-frozen foods, and the use of the
tray as a baking mould, is that it can easily be opened by simply
folding up the edge flaps and then folding out the end walls and
side walls of the tray to release the deep-frozen goods such as
ice-cream or the prepared pastry.
Some suitable embodiments of the blank and tray according to the
invention are shown as examples in the accompanying drawings.
FIG. 1 shows an embodiment of the blank for the formation of a tray
with tight corners, FIGS. 2, 3 and 4 show in perspective various
stages of the tray during erection thereof, FIG. 5 shows one end of
the erected tray seen from the inside, FIG. 6 is a perspective view
of the erected tray, FIG. 7 shows an end section of another
embodiment of the blank according to the invention with freely
projecting end flaps, FIG. 8 shows one end of a tray erected from
the blank in FIG. 7 with the end flaps on the outside of the tray,
the edge flaps being folded down towards these end flaps, whilst
FIG. 9 shows one end of a tray erected from the blank in FIG. 7
with the end flaps on the inside of the tray and the edge flap
folded down over these end flaps.
The blank in FIG. 1 and the corresponding tray in FIGS. 2 to 6
consist of a bottom 10, two side walls 12, 14 and two end walls 16,
18. The side walls are extended with end flaps 20, which in the
example shown consist of corner sections between the ends of the
end walls and the side walls and can be folded along edge folding
lines 22, 24 and diagonal folding lines 26 in a manner known per
se.
At their upper edges the end walls are extended by edge flaps 28
which can be folded along straight, or essentially straight,
transverse folding lines 30. The end wall 16 can be folded relative
to the bottom 10 by folding along an arc-shaped folding line 32.
The side walls have edge flanges 34 which are extended by locking
flaps 35.
When the end wall 16 is folded up, it will be forced into an arc
shaped position, as shown in FIGS. 2 and 3, due to the fact that
folding line 32 has an arcuate shape. In this position the end
flaps 20 are folded in towards the outside of end wall 16 and then
the edge flap 28 is folded down over the end flaps as shown in FIG.
4.
After folding down the edge flap 28 end wall 16 and the folded down
edge flap 28 will be kept in the arc shaped position as shown in
FIGS. 5 and 6. In practice folding line 30 between edge flap 28 and
end wall 16 will not normally bend out as much as folding line 32
between end wall 16 and bottom 10, but by providing bottom folding
line 32 with a sufficient arc shape, sufficient bending of the edge
flap folding line 30 in the erected tray is also obtained so that
the edge flap can be locked in its folded down position.
The tray shown in FIG. 6 has liquid tight corners. It can easily be
opened by folding up the edge flaps. If the blank has a heat
sealable coat, an extra locking action can easily be obtained by
heat sealing, but this should not be necessary in most cases.
FIG. 7 shows a blank corresponding to the blank in FIG. 1 with the
difference that end flaps 36, which can be folded along a folding
line 38, are freely projecting from the ends of the side walls, and
that the side walls have no edge flaps. When erecting this blank,
end flaps 36 can alternatively be placed on the outside of the end
wall as shown in FIG. 8 which gives the tray a smooth inside, or
end flaps 36 can be placed on the inside of the end wall as shown
in FIG. 9, which gives the tray a smooth outside. In the first case
edge flap 28 is folded down towards the outside of the end wall,
and in the second case it is folded down towards the inside of the
end wall. In both cases locking of edge flap 28 is obtained in its
folded down position due to the arc-shaped bottom fold 32.
In the examples shown, bottom folding line 32 on the blank in FIGS.
1 and 7 is provided to form an arc which is curved towards folding
line 30 between edge flap 28 and end wall 16 so that the exterior
surface of each end wall 16, 18 has a convex contour, but it is
also possible to curve bottom folding line 32 in the opposite
direction so that the exterior surface of each end wall 16, 18 has
a concave contour and still obtain the locking action according to
the invention.
A further important advantage of the blank according to the
invention is that it can have a relatively small material thickness
with minimal rigidity. This does not prevent the locking action
according to the invention from being obtained for the formation of
a tray with satisfactory locking action at the corners for a large
number of applications.
In the examples shown, the tray walls form an essentially right
angle with the bottom, but they may also incline outwards to enable
the trays to be stacked on top of each other.
* * * * *